This invention relates to the fields of intervention, surgery, and more particularly to method and apparatus for treatment of aneurysms.
An aneurysm is a condition in which a portion of a vessel has a weakened wall that results in the expansion of the vessel due to internal pressures. Aneurysm may be an aortic aneurysm occurring in the abdominal area or in other areas, including but not limited to: aneurysm in the thoracic aorta and neurovascular aneurysms.
Aortic aneurysm results from abnormal dilation of the artery wall and is often associated with arteriosclerotic disease. Unless treated, an aneurysm can rupture, leading to severe and often fatal hemorrhaging. Treating an aortic aneurysm generally involves transplanting a prosthetic graft to bridge or bypass the affected portion of the aorta. Surgical implantation of the graft is possible but this treatment causes considerable trauma, results in high mortality and morbidity and, even when completely successful, requires a lengthy recuperation period. Due to the difficulty of the operation, surgical replacement is even less attractive when it must be performed on an emergency basis after the aneurysm has ruptured.
A less invasive alternative involves the use of a catheter for intraluminal delivery of a graft. Graft delivery systems can employ a graft with expandable portions that anchor the graft in the aorta. Often, the systems use an inflatable balloon on the delivery catheter to expand the anchoring portion of the graft as disclosed in U.S. Pat. No. 5,275,622 (Lazarus et al.) which is hereby incorporated in its entirety by reference thereto. This latter example requires the use of a bulky capsule to store the graft and a complicated pushrod system to deploy the graft.
The success of a percutaneous vessel repair depends in large part on getting the graft to the location of the vasculature in need of repair and deploying the graft effectively. A difficulty associated with graft deployment and its effectiveness is blood flow-by which occurs when blood can pass between the graft and the patient""s vessel wall, bypassing the graft.
Although the referenced prior art systems and others employ many different stent and graft configurations, the limitation of complete aneurysm containment has not been met.
These systems are frequently too bulky and inflexible to access many regions of a patient""s vasculature. In addition when using endovascular stent grafting, it is important to know the diameter, length, and healthy neck length segment of the aneurysm in order to prevent perigraft leaks caused by poor arterial apposition or by foreshortening of the endovascular graft.
In the neurovascular applications, a particular example for aneurysm repair is the treatment of an aneurysm by placing radiopaque materials within an aneurysm pouch. For example, it is known to push embolic coils through an introducer catheter. However, once the embolic coils leave the introducer catheter they are no longer under control and may become repositioned away from the desired location. This might occur, for example, when the treatment site is located near a vessel having a larger lumen, as when the embolic coil, having migrated to the larger vessel, would travel to a remote location. Other disadvantages include the possibility of the coils rupturing the wall of the aneurysm sac or the further expansion of the aneurysm.
Another example of vulnerable tissue sites other than aneurysms include vein grafts implanted as a bypass graft in CABG procedures. A disadvantage of a vein graft is that it may degrade over time as a result of the vein structure not being adept to effectively handle high arterial pressure (e.g., being a weaker structure against pressure), thereby degrading and occluding over time. Typically, by the time intervention takes place, the vein graft has degraded or occluded thus making it difficult to salvage or treat.
Thus, what has been needed is a method and device that can provide less invasive and more effective treatment of vulnerable tissue sites, in particular arterial and other aneurysms. The present invention satisfies at least some of this and other needs.
The present invention is directed to a method and apparatus for treating vulnerable tissue sites such as aneurysms in the abdominal or thoracic aorta. Other applications of for the method and apparatus of the present invention include neurovascular aneurysms, veins, vein grafts, and expanded or thinned tissues on various organs and body surfaces.
The apparatus of the present invention, is directed to containment members for at least partially containing a vulnerable tissue site, thus preventing or minimizing the further vulnerability or growth of the site. Additionally, or alternatively, the containment members can apply resistive force to the vulnerable tissue site. The force can be compressive against the exterior surface of the tissue site. The containment members of the present invention can be used alone or in combination with support members, such as stent/grafts, in treating a tissue site. In this embodiment, the support member is disposed within the inner lumen of the vulnerable tissue site with the containment member disposed on the exterior surface of the lumen.
The containment members may totally encircle the vulnerable tissue site or they may be disposed about less than the entire circumference of body lumen including the vulnerable tissue site. In one embodiment, the containment members have a containment surface of sufficient dimensions to at least partially encircle a region of the vulnerable tissue. In another embodiment, the containment member can be configured to provide a compressive force against the vulnerable tissue. The containment members may be configured for attachment to a positioning member. The positioning member can be configured for securing the containment member to an adjacent tissue site or body part to minimize further vulnerability of the tissue site. In another embodiment, the positioning member is configured to be biased against an adjacent healthy tissue site or body part.
The various embodiments of the containment members of the present invention can be configured to deliver agents, such as therapeutic agents, to the tissue site. Additionally, the containment members can be configured to accommodate different anatomical settings having vulnerable tissue sites. The embodiments include but are not limited to strands, coils, sheaths, omega shaped coils for structures that can not be looped around entirely, and inflatable containment members.
The containment member may be formed of polymeric or metallic material to remain in place until the removal of the same, or in the alternative may be formed of biodegradable material, degrading over a period of time.
In operation, the containment members of the present invention may be introduced to the vulnerable tissue site in one of several ways, including: (1) surgical methods, such as cut-down or laparoscopically; (2) intra-endoscopically, i.e., through the same body conduit or lumen as the one including the vulnerable tissue; and (3) inter-endoscopically, i.e., through, at least in part, a body conduit or lumen adjacent the conduit which has the vulnerable tissue.
In one embodiment, the containment member is advanced through the first lumen of the first tubular member including the vulnerable tissue site and through an access site in a wall of the first tubular member and is disposed about an exterior surface of the tissue site.
In another embodiment, the access site is part of a second tubular body member having a second lumen and disposed, at least in part, substantially parallel and adjacent the tissue site. In this embodiment, the containment member is advanced through the second tubular body and through the access site located in a wall of the second tubular body and disposed about an exterior surface of the tissue site. The containment member can be disposed about the exterior surface of the first body lumen which includes the vulnerable tissue site alone or together with the exterior surface of the second body lumen.
As defined herein, vulnerable tissue site includes, without limitation, any tissue site which is or can be weakened, enlarged, thickened, or thinned, either permanently or periodically (as for example during different phases, cycles, or conditions). The vulnerable tissue may be present in any area of a host body, such as but not limited to: cardiovascular or neurovascular arteries or veins, vein grafts such as saphenous vein graft for a pass surgery, aorta including abdominal and thoracic, vena cava including inferior and superior, organs such as stomach or glands. The vulnerable tissue site may be native to the intracorporeal body or it may be a transplanted intracorporeal body such as a saphenous vein graft introduced to the body as a result of a procedure such as bypass before it becomes weakened as a result of its new environment.